Method and program for identifying errors

Abstract

A method for identifying geometric errors with respect to at least two translational axes and at least one rotational axis of a machine using a control device is disclosed. The method comprises the steps of: measuring positions of a jig in three-dimensional space using a position measurement sensor, wherein a measurement is carried out when the jig being indexed around the rotational axis by a plurality of angles is located at the positions; approximating a plurality of measured values of the positions measured in the measuring step to a circular arc; and calculating an error in regard to a center position of the rotational axis and / or a tilt error in the rotational axis, and tilt errors in the translational axes, based on the circular arc resulting from the approximating step.

Description

This application claims the entire benefit of Japanese Patent Application Number 2009-186735 filed on Aug. 11, 2009, the entirety of which is incorporated by reference.BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to a method and a program for identifying geometric errors of a machine having translational and rotational drive axes.2. Description of Related ArtAs an example of a machine having translational and rotational drive axes, there is known a machine tool for processing parts or metal molds. Such a machine tool can process a workpiece into a desired shape by a material removal process including relative movements of both or either of a tool and a workpiece while rotating the tool or the workpiece.As an example of this machine tool, FIG. 1 shows a schematic view of a three-axis control machining center (three-axis machine) having three translational axes. A spindle head 2 is allowed to make a translational movement with 2 degrees of freedom ...

AI Technical Summary

Benefits of technology

With this configuration, in addition to the above advantageous effects of the identification method according to the first aspect of the invention, while maintaining the accuracy, a more simple identification method can be realized.

of the identification method according to the first aspect of the invention, while maintaining the accuracy, a more simple identification method can be realized.

According to an alternative preferred embodiment of the aforementioned identification method, the approximating step may comprise determining a radius of the circular arc by measuring a distance from a center of the rotational axis to the plurality of measured values, and the error calculating step may comprise calculating the geometric errors in regard to the rotational axis from first-order components of the circular arc.

With this configuration too, in addition to the above advantageous effects of the identification method according to the first aspect of the invention, while maintaining the accuracy, a more simple identification method can be realized.

According to another preferred embodiment of the aforementioned identification method, the machine may have more than two rotational axes, and in the measuring step, more than two angles may be indexed for measurement based on one rotational axis other than the rotational axis from which the plurality of angles are indexed.

With this configuration, in addition to the above advantageous effects of the identification method according to the first aspect of the invention, even if a more complicated machine is employed, geometric errors can be identified in a simple and accurate manner.

Problems solved by technology

With these configurations of the aforementioned identification method and program, not only geometric errors in regard to the rotational axes but also geometric errors in regard to the translational axes can be identified.

Further, if a touch trigger probe is used as a position measurement sensor, since the touch trigger probe is relatively cheap and easily obtainable, geometric errors can be easily identified.

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